Or would perhaps trading opamps for ferrite in the signal path be a bad swap.

I used coils to make LC notch filters for the electronics on my
full range w/ woofer systems. Simple and nice replacement
for equivalent op amp circuit. They have some nice 100 mH
type parts in the Digikey catalog.

I wonder if F5 (turbo? v1,2,3?) would be a good match for the new LX521. (Gain of F5 is only 15db iso the recommended 26db)
Maybe the woofer channel could be done with hypex modules (more power reserves) and mid/tweet with F5?

For my bi-amped system, I use a BOSOZ which drives a line level analog crossover consisting of coils and capacitors..the crossover terminates into Aleph J's...

This all replaced an active Marchand crossover which was heavy on Op Amps.

I much prefer the sound of the simple coil and capacitor filters. As diyers, we can do this because we know what the impedences of the stages before and after the filter.

The BOSOZ is very cool in this application because the BOSOZ lets you adjust the gain of the high and low channels without changing the output impedence of the preamp channels. (the analog filters would be affected if the output impendance of the BOSOZ changed as you adjust levels) So you can change levels of the high channel and low channel to suit your taste.

SL if clear on amplification. He recommends power levels, that amplifiers all have same gain; and logical extension is that all amplifiers have identical response, easiest when amplifiers are identical.

SL if clear on amplification. He recommends power levels, that amplifiers all have same gain; and logical extension is that all amplifiers have identical response, easiest when amplifiers are identical.